ADAPTER FOR A CONTAINER WITH A STIRRER

Abstract: A container (1) comprising edges (13) forming an opening in the container (1) and a stirrer (2) arranged in the container for stirring a mixture, wherein an adapter (4), comprising a tubular part (6, 8) formed with a cross section corresponding to the cross section of the opening in the container (1), is fitted to the edges (13) of the container. The tubular part (6, 8) of the adapter has a first and a second opening (11 and 12, respectively). Alternatively, the second opening (12) of the adapter is provided with a lid (7) with a third opening (5). The first opening (11) is fitted to the edges (13) of the container and the second or third opening (12 or 5) allows passage of compound, cement powder, additives, etc., and a drive means (9) for driving the stirrer (2). Upon rotation of the stirrer (2), a wave is created in the mixture which is prevented by the adapter (4) from overflowing the edges (13) of the container (1). In this way, the volume of the container is utilized more efficiently since the container (1) can be filled to a higher level without the risk of overflowing occurring.

Description: ADAPTER FOR A CONTAINER WITH A STIRRER TECHNICAL FIELD The present invention relates to a method and a device for more efficiently utilizing the volume in a container, for example an ultimate waste disposal container, for a mixture. The mixture is stirred in the container for the purpose of mixing a first compound, for example radioactive waste, with a second compound, for example cement powder including addi¬ tives, by means of a rotating stirrer which is connected to a drive means through an opening in the upper part of the container. BACKGROUND ART, PROBLEMS Methods and devices for handling radioactive waste in different types of nuclear installations are well-known. One way of taking care of a first compound, for example radio- active waste, is to mix it by stirring it with a second compound, for example cement powder, so as to form a mixture and to allow the mixture to solidify in a container, for example an ultimate waste disposal container. The container comprises edges which form an opening in the container. A stirrer is arranged in the container for stirring the mixture in the container. A drive means is connected to the stirrer through the openin, of the container while the mixture is being stirred. After the mixture has been stirred, the • container is sealed by a lid and the stirrer remains in the container. The problem is that, upon rotation of the stirrer in the container, a wave is created which results in the mixture overflowing the edges of the container. To avoid overflow, the container is only filled to a certain level below the edge of the container. This method results in a void being created in the upper part of the container, whereby the volume of the container upon ultimate waste disposal is not utilized in full. One method for preventing the mixture in the container from overflowing during stirring is to arrange a lid over the opening of the container. The disadvantage of this method is that the wave which arises during rotation of the stirrer gets stuck, through hydrodynamic forces, to the underside of the lid and thus disturbs the process of the stirring. A further disadvantage is that the lid after having been in contact with the " mixture in the container is polluted and must be cleaned or taken care of. Cleaning entails costs or may be complicated, as in the case of, for example, radioactive pollution. It is an object of the invention to provide a method and a device in which the volume of the container is utilized more efficiently as compared with the prior art. A further object is to prevent the mixture contained in the container from overflowing the edges of the container. An additional object is to take care of the device which is polluted by the mixture. SUMMARY OF THE INVENTION, ADVANTAGES The invention relates to a method for utilizing the volume of a container more efficiently, and to an adapter for carrying out the method. The method comprises fitting an adapter to the edges of a container which form an opening in the container. A mixture of a first compound, for example radioactive waste, mixed with a second compound, for example cement powder including additives, are stirred in the container with the aid of a stirrer. The wave which is created during the stirring of the mixture is prevented by the adapter from overflowing the edges of the container. The adapter is detachable after com¬ pleted stirring. The adapter comprises a tubular part with a cross section corresponding to the cross section of the opening in the con¬ tainer. The adapter has, for example, the shape of a cylinder, but other shapes such as square, oval, or triangular shape are also feasible depending on the shape of the container. The tubular part has a first and a second opening wherein the first opening makes contact with the opening of the container and the second opening allows the passage of the second compound and a drive means to the stirrer in the container. Alternatively, the second opening of the tubular part is provided with a lid with a third opening for the passage of the drive means . To the second or the third opening there is connected a member for achieving ventilation to take care of dust and aerosols which arise during the stirring. One suitable way of taking care of the adapter polluted by the mixture is to move it down into the container and ultimately storing it together with the mixture and the stirrer in the container. Such a once-for-all use of the adapter is justified by the fact that it is more costly to clean the adapter than to refrain from further use thereof. One way of moving the adapter down into the container is to lift the container against a tool, by means of a hydraulic lifting device, with the adapter arranged to the opening of the container, such that the adapter is pressed down by means of the tool into the container. An alternative method involves arranging the adapter fixed to the ventilating member. The ventilating member together with the adapter are connected to the opening of the container while stirring, whereupon the ventilating member and the adapter are dismantled and reused for the stirring in a plurality of containers. In this case, the mixture in the container is a radioactive waste slurry mixed with cement powder, but the method described is also suited for other types of compounds, such as chemical waste, liquids, and paint. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in greater detail by descrip¬ tion of a few embodiments with reference to the accompanying drawings. Figure 1 shows a container comprising edges which form an opening, a stirrer arranged in the container, and an adapter fitted to the opening of the container. Figure 2 shows an adapter according to the invention. Figure 3 shows an alternative embodiment of an adapter. DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 shows a container 1 which comprises edges 13 forming an opening in the container 1. A stirrer 2 comprising paddles 3 is arranged in the container 1. An adapter 4 is fitted to the inside of the edges 13 at the opening of the container. The adapter 4 in Figure 1 is also shown in Figure 2. The adapter 4 comprises a tubular part 6 with a cross section corresponding to the cross section of the opening in the container 1. The tubular part 6 has a first opening 11 and a second opening 12. The second opening 12 is provided with a lid 7 with a third opening 5. The stirrer 2 is connected to a drive means 9 through the third opening 5 of the adapter 4. A member 10, to achieve ventilation to prevent dust and aerosols which arise during the stirring from spreading to the surrounding atmosphere, is arranged around the drive means 9 and to the third opening 5 of the adapter 4. During rotation of the stirrer 2, a wave is created in the mixture which is prevented by the adapter 4 from overflowing the edges 13 of the container 1. Since the volume of the mixture in the container 1 may be increased by the connection of the adapter 4 during the stirring, the invention results in the volume in the container 1 being utilized more efficiently. After the stirring, the adapter 4 is moved down into the container 1 by lifting the container 1, with the adapter 4 fitted to the opening of the container 1, by means of a hydraulic lifting device 14 against a separately placed tool 15 such that the adapter 4 is moved down into the container 1 by means of the tool 15. Figure 3 shows an alternative embodiment of the adapter 4 comprising a cylinder 8 with a first and a second opening, 11 and 12, respectively. In this case, the stirrer 2 is connected to the drive means 9 through the second opening 12. The ventilating member 10 is arranged in the second opening 12. The adapter 4 is preferably made of plastic, but also other materials are feasible, such as metal or paper.

Claims: CLAIMS 1. A method for more efficiently utilizing the volume in a container (1) which comprises edges (13) which form an opening in the container (1) and a stirrer (2) arranged in the container (1) for stirring a mixture of a first compound, for example radioactive waste, with a second compound, for example cement powder, characterized in that an adapter (4) is fitted to the edges of the container such that a wave of the mixture, formed during rotation of the stirrer, is prevented from overflowing the edges of the container and that the adapter after the stirring is dismantled. 2. A method according to claim 1, characterized in that the adapter (4) is arranged on the inside of the edges (13) of the container (1) and that when the stirring is completed, the adapter is moved down into the container whereby the adapter, polluted by the mixture, is taken care of. 3. A method according to claim 2, characterized in that the adapter is moved down into the container by lifting the container, preferably by means of a hydraulic lifting device (14), against a tool (15) such that the adapter is moved down into the container. 4. A method according to claim 1 or 2 , characterized in that a member (10), for achieving ventilation, is connected to the adapter (4) via an opening (5, 12), thus preventing the spread of dust and aerosols from the mixture. 5. A method according to any of the preceding claims, characterized in that the adapter is used to increase the volume of the mixture during solidification of radioactive waste in a cement mixture in an ultimate waste disposal con- tainer wherein the stirrer after completed stirring remains in the container. 6. An adapter (4) for a container (1), wherein the container (1) comprises edges (13) which form an opening in the container (1) and a stirrer (2) arranged in the container (1) for stirring a mixture of a first compound with a second compound, characterized in that the adapter (4) comprises a tubular part (6, 8) with a cross section corresponding to the cross section of the opening in the container (1) and that the adapter (4) has a first and a second opening (11 and 12, respectively), wherein the first opening (11) is fitted to the edges (13) of the container and the second opening (12) allows the passage of the second compound and a drive means (9) to the stirrer (2) in the container (1) . 7. An adapter according to claim 6, characterized in that the second opening (12) of the adapter is provided with a lid (7) with a third opening (5). 8. An adapter according to claim 6 or 7, characterized in that a member (10), for achieving ventilation, is fitted to the second or third opening (12 or 5) of the adapter to prevent the spread of dust and aerosols from the mixture.

Inventors: SALOMON HEINZ, TORSTENFELT BOERJE, SALOMON, HEINZ, TORSTENFELT, BOERJE
Applicants: ASEA ATOM AB, SALOMON HEINZ, TORSTENFELT BOERJE, ABB ATOM AB, SALOMON, HEINZ, TORSTENFELT, BOERJE
Application year: 1994
Main classification: G21F5
IPC codes: B01F15, G21F5